A couple has one girl and is expecting a second child. What is the probability that this child will be a boy? After several years and several births, this couple now has six daughters and is expecting a seventh. What is the probability that this child will be a boy?

50%

Describe the centromere and kinetochore

kinetochore = where the spindle fibers attach during cell division to pull the chromosomes apart. It is attached to the centromere.

X-linkage in pedigrees is often identified by what characteristic of the pedigree?

criss cross pattern

Crossing over (genetic recombination) occurs in

answer A

Meiosis I Prophase

Permanent, heritable changes in genetic information (DNA) are called

mutations

Homologous chromosomes are those that can be matched by virtue of their similar structure and function within a nucleus. What chromosomes making up the human genome do not follow the same characteristics of homology?

X Y

The "distance" between two linked gene pairs can be expressed as a percentage. Name the unit based on percent recombination that was created in honour of the scientists who pioneered the use of fruit flies for genetic research.

centimorgan

Human females with XY chromosomes and a mutation in their receptor gene have ____________________ syndrome.

androgen insensitivity syndrome

_____ is a change in allele frequency of a population over time.

continuous variation

A spontaneously aborted human embryo is characterized with respect to karyotype, and it is found to be normal except that it contains only one chromosome number two. This is an example of what type of aneuploidy?

monosomy

__________________ refers to the splitting of the cytoplasm, separating one cell into two.

cytokinesis

What does it mean if a human female oocyte is no longer arrested in metaphase II of meiosis?

oocyte is ready to be fertilized (ovulation)

Interactions among the human ABO blood group alleles involve _______ and ________.

co-dominance

epistasis

What is the probability of obtaining 3 heads in four flips of a fair coin?

.0625

Linked genes ____________.

co-segregate

If a couple with Sickle cell disease genotypes Ss and Ss mate and have one child with the disease, what is the chance the next child has the disease as well?

.25

A diploid somatic cell from a rat has a total of 42 chromosomes (2n = 42). As in humans, sex chromosomes determine sex: XX in females and XY in males.

What is the total number of telomeres (protective part at the end of a chromosome) in a rat cell in G2?

84

A rare dominant trait, when exhibited in men, is transmitted to half their sons and to half their daughters. The gene for this trait is carried:

on an autosome

In the following tetrahybrid cross AaBbCcDd x AaBbCcDd what proportion of the F2 offspring would be expected to be phenotypically ABCD ?

81/256

Which term refers to mating between closely related people?

consanguinity

In a germ-line cell from a human male that is dividing, when do the X and Y chromosomes segregate?

Meoisis I anaphase

If a typical somatic cell has 32 chromosomes, how many chromosomes are expected in each gamete of that organism?

16

If thymine makes up 15% of the bases in a certain DNA sample, what percentage of the bases must be cytosine?

35%

In snapdragons, heterozygotes for one of the genes have pink flowers, whereas homozygotes have red or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers?

50%

How many Barr Bodies would you expect to see in an XXY individual?

1

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

50%

Which of the following parental genotypes will produce only heterozygous F1offspring?

AA x aa

A single gene can only have two alleles

false

Linkage analysis can be performed using haploid organisms.

true

Recombination can only occur through crossing over.

true

A proband is the first affected person that comes to the attention of a geneticist and from whom a pedigree is initiated.

true

Mapping experiments become more accurate as the distance between genes increases.

true

Heterozygous genetic screening is used to identify individuals who are healthy but carry alleles that have the potential to produce affected children.

true

What are the genotypes of a pure-breeding purple vestigial fly and a purebred red normal fly?

prpr/vgvg and pr+ pr+/ vg+ vg+

What do we get if we cross these two pure-breeding lines? Give the genotype and the phenotype.

The results that Morgan got were not what you would expect. Instead, he saw fewer of the purple normal (pr pr vg+ vg ) and red vestigial (pr+ pr vg vg). What do these results tell us about the gametes produced by the original heterozygote?

There were many more pr vg and pr+vg+ gametes produced by the original heterozygote.

Two autosomal genes in Drosophila code for eye color and wing shape (the wild type is dominant). The genetic symbols for these traits are for eyes: pr: purple and pr+: red and for wings vg: vestigal and vg+: normal.

How did Morgan explain these results?

Morgan proposed that the unusual ratios were a result of linkage and that the genes for eye color and wing shape must be on the same chromosome and usually inherited together.

Explain why mitosis does not produce genetic variation and how meiosis leads to the production of tremendous genetic variation.

crossing-over

Describe the difference between: genome and gene

genome = includes both the genes and the non-coding sequences of the DNA

gene= a unit of heredity in a living organism. It is normally a stretch of DNA that codes for a type of protein or for an RNA chain that has a function in the organism.

The complete genetic makeup of any organism is its

genome

Chromosomes are in unseparated, sister-chromatid form, at the end of which phase(s)?